Do *NOT* Buy A Duplex Water Softener Until You Read This

Article Last Updated: August 2022

Getting a duplex water softener is necessary if you have hard water in a large home with a lot of demand. Regular single tank softeners can treat enough hard water for the average 1-3 family home.

SpringWell Whole House Softener Filter ComboHowever, a larger family home or business premise might need a “twin tank” or duplex water softener.

A two tank system means that it can cope with a larger volume of water needs. This is because the machine never has to stop working as one tank will rest while the other is working.

What is hard water and why is it a problem?

Hard water is when “hard minerals” like calcium and magnesium ions are present in water and causes white limescale stains in and around your kitchen / bathroom appliances.

The simple way to know if you suffer from hard water is look inside your kettle. If it is full of white and flaky scales at the bottom then you have hard water.

It is not great to consume lots of hard water from a health perspective but the bigger problem is what hard water does to your pipes and appliances.

The only guaranteed way to treat hard water is with a water softener. There are many softener types on the market that include simplex, duplex and triplex.

A Simplex Water Softener System

Inside A Water SoftenerSimplex water softener systems are softeners that only have one tank.

These are by far the most common type of water softener that you can buy on the market today and are usually the cheapest too.

Simplex water softeners are best for situations where there is a steady demand for moderate capacities of soft water in a day.

This allows you to regenerate when you reliably know that soft water will not be needed (usually late at night).

Red CrossThe Biggest Flaw?

The main disadvantage of a simplex water system is that it can not produce soft water 24-7 like the other types of softener systems.

What is a Duplex Water Softener?

Duplex water softeners are high capacity softeners that are suitable for dealing with high levels of hard water and locations that need an uninterrupted supply of softened water.

They do this with 2 tanks instead of 1. Hence the name “duplex”, which comes from “duo” – the latin word for 2.

Aquasana Whole House UV FilterThe double tank system allows one resin container to always operate while the other is in regeneration or standby mode. This ensures 24/7 soft water production.

Duplex softeners typically come with a controller, which allows you to set the beginning of the regeneration cycle with the timer, the quality of the water or the quantity produced.

Duplex Water Softener Tips:

Water softeners are generally very reliable devices. However, a low level of regular attention is necessary to make sure that they provide good service over a longer period of time.

  • You should consider getting a routine professional service by an experienced service team. This will ensure the safety and continued high quality operational performance of your machine.
  • A timed or automated device works best when the daily need for soft water is relatively constant. You simply have to set the duplex softener machine to regenerate when overall consumption is low (usually late at night).
  • On the other hand, counter-controlled (on demand) models are ideal when daily water demand is variable.
  • High-purity softener salt is necessary to ensure the smooth running of the brine tank.

Triplex Water Softener System

As the name suggests, a triplex system is a water softener that has 3 tanks.

Tripple RO MachineThis is usually a bespoke system but there are a few triplex water or heavy duty softeners available for immediate purchase online.

A bespoke model might combine a simplex system combined with a duplex system. This means there can also be customized quadplex or multiplex water softeners.

Triplex systems are commonly used in the industry where production requires a sudden influx of softened water at peak times. If necessary, two of the three tanks will start regenerating to meet a spike in demand.

The third container is then available as soon as the other two resin beds are exhausted.

The Best Duplex Water Softener System?

As has been mention a duplex system is one that consists of two tanks containing ion softeners.

Water Softener ValveAs soon as the first tank of resin has run out and is being regenerated, the second tank comes into operation. This keeps the water running at all times.

This unit is particularly useful in a commercial or industrial environment where closing a production line for 2 hours would seriously effect the bottom line.

You can normally control Duplex softeners by the meter.

I have written many times how good this range is (Read: My Fleck review here). The Fleck duplex system is the 9100SXT and is by far one of the best duplex’s in my opinions.

Duplex Water Softener Price?

You can get a twin duplex water softener for upwards of $2300.

Mr Water Geek ThinkingBuying it from Amazon is a good idea because you can benefit from all the reviews from other customers before you buy.

Also, you benefit from free next day delivery, an Amazon accredited plumber to install it for you which means you can theoretically have your very own duplex water softener installed by the end of tomorrow.SpringWell Whole House Softener Filter Combo

Finally, their customer service is far better than that provided by many water companies so you have access to extra support if anything goes wrong.

But remember that most machines that come from places like SpringWell come with guarantees and lifetime warranty.

Aquasana Salt Free Softener and Filter System

(Conditioner & Filter)

SpringWell Whole House Filter & Salt Softener

(Traditional Salt Water Softener & Filter)
Aquasana Whole House Filter
Pelican Softener with Filters
- Powerful salt-FREE water softener.
- 1,000,000 one million gallon capacity.
- Aquasana Rhino exceeds NSF standards.
- Treats hard water WITHOUT salt.
- Removes chlorine, bacteria, iron, sulfide, manganese, mercury, lead etc.
- Includes pre-filter, copper-zinc and carbon filtration stages with standard fittings.
- Treats hard water up to 25 ppm WITHOUT needing salt.
- 90-Day Pure Satisfaction Guarantee.
- Powerful salt-BASED water softener.
- Also includes a multi-stage filter.
- Easy installation (inside or outside)
- 6 month satisfaction guarantee and limited lifetime warranty.
- Sufficient for 1-3 bathrooms (options for more bathrooms available).
Does NOT require electricity or back-flushing.Requires electricity if using the electronic head monitor.
N/AEffectively treats: calcium and magnesium.
Control Your System With An App:? NOControl Your System With An App:? YES
Treats hard water UP TO 25 ppm (low to medium low hard water).Treats hard water OVER 25 ppm (medium to extremely hard water).
Sale prices automatically applied by clicking this link.
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Ships to US and CA.
Ships to US, CA and Puerto Rico.
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About The Author

About The Author Of This Post

I'm Luke and I enjoy researching, testing and writing about water treatment products. Read full bio.